Simple Encryption You Can Do On Paper

May 12, 2021 by 2 Comments

It’s a concern for Europeans as it is for people elsewhere in the world: there have been suggestions among governments to either outlaw, curtail, or backdoor strong end-to-end encryption. There are many arguments against ruining encryption, but the strongest among them is that encryption can be simple enough to implement that a high-school student can understand its operation, and almost any coder can write something that does it in some form, so to ban it will have no effect on restricting its use among anyone who wants it badly enough to put in the effort to roll their own.

With that in mind, we’re going to have a look at the most basic ciphers, the kind you could put together yourself on paper if you need to.

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Mind-Controlled Flamethrower

May 12, 2021 by 9 Comments

Mind control might seem like something out of a sci-fi show, but like the tablet computer, universal translator, or virtual reality device, is actually a technology that has made it into the real world. While these devices often requires on advanced and expensive equipment to interpret brain waves properly, with the right machine learning system it’s possible to do things like this mind-controlled flame thrower on a much smaller budget. (Video, embedded below.)

[Nathaniel F] was already experimenting with using brain-computer interfaces and machine learning, and wanted to see if he could build something practical combining these two technologies. Instead of turning to an EEG machine to read brain patterns, he picked up a much less expensive Mindflex and paired it with a machine learning system running TensorFlow to make up for some of its shortcomings. The processing is done by a Raspberry Pi 4, which sends commands to an Arduino to fire the flamethrower when it detects the proper thought patterns. Don’t forget the flamethrower part of this build either: it was designed and built entirely by [Nathanial F] as well using gas and an arc lighter.

While the build took many hours of training to gather the proper amount of data to build the neural network and works as the proof of concept he was hoping for, [Nathaniel F] notes that it could be improved by replacing the outdated Mindflex with a better EEG. For now though, we appreciate seeing sci-fi in the real world in projects like this, or in other mind-controlled projects like this one which converts a prosthetic arm into a mind-controlled music synthesizer.

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Testing 3D Printed Worm Gears

May 12, 2021 by 12 Comments

Worm gears are great if you have a low-speed, high-torque application in which you don’t need to backdrive. [Let’s Print] decided to see if they could print their own worm gear drives that would actually be usable in practice. The testing is enlightening for anyone looking to use 3D printed gearsets. (Video, embedded below.)

The testing involved printing worm gears on an FDM machine, in a variety of positions on the print bed in order to determine the impact of layer orientations on performance. Materials used were ABS, PLA and PETG. Testing conditions involved running a paired worm gear and worm wheel at various rotational speeds to determine if the plastic parts would heat up or otherwise fail when running.

The major upshot of the testing was that, unlubricated, gears in each material failed in under two minutes at 8,000 RPM. However, with adequate lubrication from a plastic-safe grease, each gearset was able to run for over ten minutes at 12,000 RPM. This makes sense, given the high friction typical in worm gear designs. However, it does bear noting that there was little to no load placed on the gear train. We’d love to see the testing done again with the drive doing some real work.

It also bears noting that worm drives typically don’t run at 12,000 RPM, but hey – it’s actually quite fun to watch. We’ve featured some 3D printed gearboxes before too, pulling off some impressive feats. Video after the break.

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Play Your Favorite Nokia Game On The Raspberry Pi Pico

May 11, 2021 by No comments

In many people’s memories, Snake lived and breathed on Nokia handsets from the late 90s and early 2000s. However, the game has been around for much longer than that, and will continue to live on in the future. That’s at least in part thanks to people like [Hari Wiguna] keeping it alive by implementing it on new platforms.

[Hari] set about writing Snake in MicroPython for the Raspberry Pi Pico. The hardware side of things is simple enough – five buttons hooked up to the Pico, along with an 128×64 I2C OLED screen to display the game on. On the software side of things, [Hari] pushed the boat out, deciding that his version of Snake had to have the player character slither like the real thing. This took a little effort to get right, particularly when navigating corners in different directions. However, perseverance paid off and [Hari] got the job done.

Code is on GitHub for those that want to tinker at home. It’s a tidy piece of work, though not the weirdest place we’ve seen the game appear – we’ve actually seen it run within PCB routing software before thanks to some nifty scripting. Video after the break. Continue reading “Play Your Favorite Nokia Game On The Raspberry Pi Pico” →

Simple GUI Menus In Micropython

May 11, 2021 by 2 Comments

Love ’em or hate ’em, sometimes your embedded project needs a menu system. Rather than reimplement things each and every time, [sgall17a] put together a simple GUI menu system in Micropython that can be reused in all sorts of projects. The approach uses tables to define the menus and actions, and the demo program comes with a pretty good assortment of examples. Getting up to speed using this module should be fairly easy.

The hardware that [sgall17a] chose to demonstrate the concept couldn’t have been much smaller — it’s a Raspberry Pi Pico development board, an OLED 128 x 64 pixel display, and a rotary encoder with built-in push-button switch (it’s also been tested on ESP32 and ESP8266 boards). The widget under control is one of the commonly available Neopixel development boards. The program is hosted on GitHub, but beware that it’s under development so there may be frequent updates.

This is a good approach to making menus, but is often rejected or not even considered because of the overhead cost of developing the infrastructure. Well, [sgall17a] has done the hard work already — if you have an embedded project requiring local user setup, check out this module.

The Coffee Must Flow: Replacing A Spent Lithium Cell In A Coffee Machine

May 11, 2021 by 25 Comments

When [hacky] bought a used Douwe Egberts Gallery 200 all-in-one coffee maker, the machine was known to have a ’empty battery’. Being one of those fancy coffee makers that handle everything from the grinding of coffee beans to the application of hot water and steam, it relies on instructions for each coffee recipe. Unfortunately, it turns out that this machine stores these on battery-backed SRAM, as [hacky] found out with help from friendly folk over at the Dutch Tweakers forum.

The Douwe Egberts Gallery 200 is a rebranded machine that’s also sold in Scandinavia as the Wittenborg FB 5100. These machines have an ST M48T58 TimeKeeper module that combines 8 kB of persistent SRAM with a real-time clock. Being powered from a single coin cell (lithium carbon monofluoride chemistry), their lifespan is limited.

Replacing the coin cell in an M48T58 TimeKeeper module with AA cells.

Fortunatley, a DE-9 connector is provided on the back to provide service/maintenance access to to the hardware. Using a conveniently available programming guide for the hardware, it was easy to figure out the pinout and baud rate (9600, 8 bit, ignore parity, no flow control). This allows for reprogramming the SRAM, but without replacing the battery this data would be gone again on the next start.

Based on the ST M48T58 datasheet, it’s not clear that the clip-on module containing the coin cell and crystal can be replaced, though one could simply plug in a new M48T58 module. Or, as [hacky] did, it’s also possible to cut open the ‘SNAPHAT’ top section and wire in a replacement battery module. With two 1.5V AA cells providing the 3V to the module, it was operational again.

Next up: working out what to write to the SRAM to make the coffee flow again.

Guitar With Hot-Swappable Pickups Lights Our Fire

May 11, 2021 by 10 Comments

There’s a story that goes something like this: Chet Atkins was playing his guitar when someone remarked, ‘that guitar sounds great!’ Mr. Atkins immediately stopped playing and asked, ‘how does it sound now?’ While it’s true that the sound ultimately comes from you and your attention to expression, we feel that different pickups on the same guitar can sound, well, different from each other.

However, this is merely speculation on our part, because changing pickups is pretty serious surgery, and there’s only one company out there making guitars with hot-swappable pickups. Since their low-end model is out of most people’s price range, [Mike Lyons] took one for the team and decided to build a guitar from scratch to test out various pickups of any size, from lipstick to humbucker. [Mike] can swap them out in under a minute, and doesn’t need any tools to do it.

[Mike] modeled the swapping system on that one company’s way of doing things, because why reinvent the wheel? The pickups are inserted through the back and held in place with magnets and a pair of cleverly-designed printed pieces — one to mount the pickup to, and the other inside the pickup cavity.

As far as actually connecting the things up, [Mike] went with a commercially-available quick-connect pickup solution that uses a mini four-conductor audio plug and jack. The body is based on the Telecaster, while the headstock is more Stratocaster — the perfect visual combination, if you ask us.

We are particularly fond of [Mike]’s list of caveats for this project, especially the requirement that it had to be built using only hand tools and a 3D printer. Although a drill press would have been nice to use, [Mike] did a fantastic job on this guitar. Whether you’re into guitars or not, this is a great story of an awesome build.

What, you don’t even have hand tools? You could just print the whole guitar instead.